CLS Exam 4 (2 of 2)

Loa loa

Produces Loaiasis or fugitive or Calabar swellings

Distributed in the rain forest areas of West Africa and equatorial Sudan

Live in subcutaneous tissues including the back, chest, axial, groin, penis, scalp, and eyes in humans

Periodic appearance of MICROFILARIAE in peripheral blood in maximal numbers during daylight hours

Any of several species of deer fly of the genus Chrysops

Insects suck blood by slicing the skin and imbibing blood wells into the wound

Worms develop to the FILARIFORM juveniles in fly's THORACIC MIUSCLE (insect chest) and then migrate to its mouthparts

Worms have tendency to wander through the subcutaneous connective tissue; this provokes inflammatory response

Remain in one spot for a short time, host reaction results in localized swellings (called Calabar Swelling)

Localized swelling from when Loa loa remain in one sport for a short time (by host reaction)

Disappears when the worm moves on

Worms have a habit of migrating through the conjunctiva and cornea of the eye and can wander across the surface of the eye

When the adult worms migrate through the conjunctiva and cornea of the eye, and wander across surface of eye

Demonstration of microfilariae in the blood

Dog heart worm

Dirofilaria immitis

Lives in the right side of the heart and pulmonary artery of dogs

Adult worm gives birth to MICROFILARIAE that enter the peripheral circulatory system

Microfilariae are then sucked up by mosquito

Microfilariae (in mosquito thoracic muscle) mature to filariform juveniles in the mosquito, migrate to mosquito proboscis

Transmitted when mosquito takes another blood meal, filariform larvae enter the wound

Mature to adulthood in HEART

Heart failure due to the worm clogging the valves

Using ELISA test on dog serum

Pedicures humans corporis

Insect that lives in the seams of clothing

Stay close to the host's body so it can feed when they need to

Eggs (nits) are cemented to the fibers in the clothes

By getting rid of the clothing! (If clothing removed, the lice will die)

Have a cap at one end to admit air

To admit air

Eggs hatch in a week and louse matures in about 8-9 days

No, does not leave the host voluntarily

When the host's body cools after death or if the person has a high fever

Pediculosis

Infestation with lice

Bites cause a red papule to develop

Red papule that causes intense itching which induces scratching which frequently lead to dermatitis and secondary infection

Intense itching (from red papule)

Leads to darkened, thickened skin (condition called Vagabond's disease)

Years of infestation of lice, leading to darkened, thickened skin

Epidemic typhus

Bacillus Rickettsia prowazekii was the agent of epidemic typhus in 1916

Bacterium is named after researchers H. T. Rickettsial and Stanislavsky von Prowazekii who died investigating it

Typhoid fever (another disease entirely)

Camp fever
jail fever
hospital fever
ship fever
famine fever

By the bite of the body louse, Pediculus humanus corporis

Typhus

Body louse

In the seams of clothing

Louse must first bite someone who is circulating the bacillus in their blood

Bacterium multiplies in the gut of the louse, eventually the bacteria will clog the louse's gut and kill it

Rickettsia prowazekii

Bacteria clog the louse's gut and kills it

Bacteria in louse's gut, louse bites host to suck blood. Because it itches, pt scratches and crushes louse. Feces containing R prowazekii gets rubbed in bite wound

Louse feces containing Rickettsia prowazekii gets rubbed into the bite wound

Obligate intracellular parasite of eukaryotic cells

Must enter endothelial cells of vascular system and multiplies inside

Results in inflammation causing blockage and rupture of the small blood vessels

rickettsia in endothelial cells of vascular system and multiplies, resulting in inflammation that causes blockage of small blood vessels

incubation period is two weeks

Pt experiences severe headache, muscle pain, chills, and photophobia (sensitivity to light), high fever*

High fever can reach 102 F; can be followed by delirium and coma

Rash begins on chest about 5 days after fever appears

Spreads to trunk and extremities

Mortality rate can be 10% to 60% without adequate medical attention

Infection is treated with antibiotics using antibiotics that specialize in attacking intracellular organism; vaccine also available

Tetracycline

Seen when people are living in crowded, filthy conditions

During the winter

Prisons, concentration camps, or refugee camps;
any place where ppl are crowded together and do not have ability to bathe or change clothes

Thought more ppl died in concentration camps during WWII of epidemic typhus than gassing

Tend to follow wars, famine, and other conditions that result in mass casualties

Pediculus humanus capitis

Instead of on the body, the louse lives on the head

Head louse smaller than body louse;
body lice differentiated from head lice about 100,000 years ago at the time of origin of clothing

Head lice more common since it does not require filthy conditions to spread

Usually children (by sharing caps, rubbing heads together, etc

Sucks blood from scalp and attaches itself to the hair of the head

Attaches her nits to shafts of hair

BODY LOUSE (not head!)

Causes the hair to become matted form the exudate

Fungus develops on the hair and emits a foul odor

Phthirus pubis (pubic louse)

Lives in the pubic region but may be found in the armpits

Sucks blood from the skin of pubic area

Intense itching

Transmitted sexually although infection by contact with bedding or other objects can occur

Cemented to pubic hair

No, does not seem to transmit disease

Disease caused by parasitic mite

A plague in nursing home pts and institutionalized people

Unhygienic conditions

Sarcoptes scabies

Sarcoptes scabiei burrows under skin to lay eggs, sets up inflammation that itches intensely

Anywhere on the body but especially in looser areas of skin

Topical application of permethrin insecticide or gamma benzene hexachloride

Finding the mites on a skin scraping

Cimex lectularius

Bedbugs are obligatory bloodsucking insects

Most species feed on humans only when other prey are unavailable

Can be found in contaminated bedding but even hiding cracks in bed itself or in contaminated furniture

Bedbug pierces the skin of host with two hollow feeding tubes shaped like tongues

With one tube, it injects its saliva which contains anticoagulants and anesthetic while the other it withdraws blood of host

After feeding (5 mins), the bug returns to hiding place

5-10 mins to a bedbug to be completely engorged with blood

Can live for a year without feeding, but normally try to feed every 5-10 days

Intense itching where the bug bites

No. Though they may pass Methicillin resistant staphylococcus aureus (MRSA) or Vancomycin resistant Enterococcus (VRE) on their feed

Term for disease caused by the bacterium Yersinia pestis

The Plague

Bubonic plague
pneumonic plague
septic plague

By being bitten by a flea (Xenopsylla Cheopis) that is infected with Yersinia pestis

Flea must have bitten infected rodent

Black rat, Rattus rattus

Zoonotic disease (because you get it from a flea that got it from a rodent)

Bc the flea vectors the bacteria

Bacteria spread rapidly to the lymph nodes and multiply

Bacilli can evade the immune system by resisting phagocytosis or once inside the phagocyte, they may multiply and kill it

Buboes

Inflamed lymph nodes swollen (due to flea)

Found where your lymph nodes are found (armpits, groin, and neck)

After the bacteria has spread to the lungs in septic plague or have been inhaled

Bacteria causes inflammation of alveoli and pneumonia sets in

Disease rapidly transmitted form human to human due to coughing and airborne respiratory droplets

Bacilli are carried inside airborne respiratory droplets and are inhaled by next victim

Through septicemia or inhalation

Occurs when the bacilli leak out of the damaged lymph nodes or lungs and get into the blood

Bacteria becomes bloodborne

Can disseminate throughout the body

1. Lymph nodes hemorrhage and become necrotic and swollen
2. Skin can discolor (red patches can turn black and necrotic)
3. Continuous vomiting of blood, body aches, headache, high fever
4. Pneumonia
5. Die (without antibiotics)

2-4 days after onset

Half

70%

ground squirrel populations

1920s